1. Field of the Invention
The present invention relates to a method and apparatus for molding. More particularly, the present invention relates to a method and apparatus for encapsulating all, or a portion, of a sheet of material and/or encapsulating structure on the surface thereof. Most particularly, the present invention relates to a method and apparatus for encapsulating all or part of a glass sheet for use as an automotive glazing. The scope of the present invention will be understood to cover the products made by the disclosed method and apparatus, as well as the particular mold structure described herein.
2. Description of the Prior Art
In the preferred embodiment of the present invention, the molding method and apparatus disclosed relate generally to glass sheets which are commonly employed as glazing closures in present day vehicles such as automobiles and the like. In addition to such glass sheets being bent to precisely defined curvatures dictated by the configuration and size of openings in the vehicle body, in order to meet strict quality standards of manufacturers, it is necessary to apply to the sheets of material items such as a gasket around a predetermined portion of the sheet of material, mounting brackets or studs at the location of the gasket, or at other positions on the surface of the sheet.
U.S. Pat. No. 4,561,625 discloses a mold structure for forming a polymeric gasket around a predetermined portion of a sheet of transparent material such as glass. The mold structure includes two cooperating mold sections for defining a chamber for receiving the transparent sheet. A seal is positioned about the periphery of the chamber and is utilized to resiliently support the sheet within the chamber. Also the seal cooperates with a predetermined portion of the transparent sheet for defining a gasket cavity having a configuration corresponding to the gasket to be formed on the sheet of transparent material.
U.S. Pat. No. 4,762,481 discloses a mold for forming a window assembly which includes a transparent glass sheet and gaskets formed by curing a polymeric gasket material in situ on the glass sheet to encapsulate a marginal peripheral edge portion thereof. A glass sheet to be utilized in a vehicle has a front edge, rear edge, and a lower edge to each of which is adhered such a gasket. In addition, a bracket means for attachment to a scissor linkage for raising and lowering the window can be secured to the lower edge of the window.
U.S. Pat. No. 4,584,155 discloses a method for molding surface structure onto the surface of a glass sheet.
While the above-mentioned patents show the forming of a gasket or encapsulation of the peripheral edge of a sheet of material, and the attachment of a bracket on the peripheral edge of a sheet of material, as well as molding onto the surface of the glass material of mold material, they do not show the attaching of a bracket onto the surface of the glass nor do they show a satisfactory apparatus for so doing. Thus, those skilled in the art continued to search for a solution of how to satisfactorily encapsulate a sheet of material while also encapsulating studs, brackets, and the like.
The aforementioned problems are addressed in accordance with the present invention by the utilization of a unique mold structure not heretofore found in the prior art, together with a novel method of using said mold structure. In its broadest form, the method and apparatus of the present invention may be used to mold almost any part which is currently injection molded. A portion of a mold cavity may be provided in a mold base, with at least one portion of a mold cavity being provided in at least one moveable mold core.
In one embodiment of the invention, the molding apparatus of the present invention is used to encapsulate a sheet of material, and includes a stationery mold base having a facing surface, a shaped surface, and slanted glass contacting surface, a shoulder portion, and a recess portion. Cooperating with the mold base is at least one movable mold core. Stop means and vacuum heads are provided in the stationary base to hold a sheet of material in proper relationship thereto such that all or a portion of the sheet of material will be encapsulated, with or without attachments, when one or more movable cores are positioned in a mating or facing relationship with said mold base.
In another embodiment of the invention, a moveable side core and a moveable top core, each having a portion of a mold cavity formed therein, will rotate into an opposed mating or facing relationship with a stationary mold base. The sheet of glass to be encapsulated will be interposed between the mold base and the cores, and may define and/or become part of the mold cavity. The portions of the glass surface and periphery on which a molding material will be deposited will be further defined by seal means. Provisions may be made in one or more of the cores to hold brackets, hinges or the like to be encapsulated either on the periphery, or the surface, of the sheet of material.
In a further embodiment of the present invention, a glass sheet having had a ceramic enamel band previously applied thereto is placed into a stationary mold base and held in place by retractable stops and vacuum heads. A moveable side core and a moveable top core, and associated seals, are rotated into position so that the facing surfaces of the mold will be adjacent and define a mold cavity. Polymeric or other molding material is introduced into the mold cavity defined thereby to encapsulate the top and side edges of the sheet of glass, as well as to apply and encapsulate a hinge onto the surface of the glass, if desired.
In a still further embodiment of the invention, a sheet of glass will be encapsulated on one surface only. A stationary mold base will have at least one slidable portion. A sheet of glass will be placed in position in the mold base, with the top and side cores open. The slidable portion of the mold base is closed. A seal in the slidable portion of the mold base will seal against a desired edge region of the glass sheet to prevent elastomeric material from molding on to, or encapsulating the edge region, the top and side cores will rotate to their closed position, and elastomeric material will be introduced into a mold cavity formed by the glass sheet and the top and side cores. After the molding process, the glass sheet will be removed, and will have encapsulation on one side or surface only.
Thus, one of the objects of the present invention is to provide a unique molding method and apparatus for injection molding a part.
Another object of the present invention is to provide a method and apparatus for encapsulating a sheet of material on one surface.
Another object of the present invention is to provide a method and apparatus for encapsulating a sheet of material on two surfaces.
Another object of the present invention is to provide an unique mold structure to provide for the encapsulation of a sheet of glass and accessories.
A further object of the present invention is to provide a part manufactured according to the foregoing method and apparatus which has one or more edges thereof encapsulated, and has a mounting bracket or hinge encapsulated proximate a surface thereof.
Further objects and advantages of this invention will be apparent from the following description and appended claims, reference made to the accompanying drawings forming a part of the specification, wherein like reference characters designate corresponding parts in the several views.